Field
Exemplary embodiment relates to a phase shift mask, a method for manufacturing the same, and a method for forming a micro pattern using the same.
Discussion of the Background
As a pattern of a semiconductor device is getting smaller, a photo mask has become one of important constituent elements thereof. The size of a semiconductor device is determined by resolution ability of photolithography, and resolution of a lithography process mostly depends on a light source of an exposure device. Recently, however, developing speed of the exposure device is unable to catch up with the miniaturization trend of a pattern of a semiconductor device. Further, since the development cost for the exposure device increases sharply, there have been attempts to implement a micro pattern through combination of a resolution enhancement technique with a light source of the existing exposure device.
One of the strongest resolution enhancement techniques is to use a phase shift mask (PSM). The phase shift mask has high resolution and high focus latitude compared to a general binary mask, and thus a micro pattern can be stably obtained through the phase shift mask.
A phase shift mask in the related art is formed by using a film that includes CrO or Mosi. In the case of the phase shift mask using the CrO or Mosi film, the degree of phase change and the degree of transmittance are determined by the thickness of the film, and it may be difficult to individually adjust the degree of phase change and the degree of transmittance.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept, and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.